1. Field of the Invention
The present invention relates to an organic thin film transistor, a method of manufacturing the same, and a flat panel display device with the same, and more particularly, to an organic thin film transistor with an improved structure, a method of manufacturing the same, and a flat panel display device with the same.
2. Description of the Related Art
Generally, a silicon thin film transistor includes a source region and a drain region doped with high-density impurities, a semiconductor layer having a channel region formed between the source region and the drain region, a source electrode connected to the source region, and a drain electrode connected to the drain region. Such silicon thin film transistor has disadvantages in that the manufacturing cost is high, and it can be easily broken by external impact, and it cannot be formed on a flexible plastic substrate because formation thereof requires a high temperature process of over 300° C.
Unlike the silicon thin film transistor, an organic thin film transistor (OTFT) using an organic semiconductor layer can be formed on a plastic substrate, etc., because it can be manufactured at the room temperature. Since the organic thin film transistor can be used in various devices such as flexible display devices, smart cards, inventory tags, and price tags, OTFTs are being vigorously developed. However, since the organic thin film transistor can not separately form a region doped with high density impurities, it has a disadvantage in that the contact resistance between an organic semiconductor layer and a source and drain electrodes is high.
In the meantime, the source electrode and the drain electrode of the organic thin film transistor are made of noble metals such as gold (Au), platinum (Pt), palladium (Pd), etc. to form an ohmic contact. However, such noble metals for the source and drain electrodes are expensive. In addition, since their adhesiveness to the organic semiconductor layer is poor, there is a high probability of failure and there is a short life span. Moreover, since such noble metals have very poor adhesiveness also to a gate insulating layer, a separate adhesive layer is additionally required. What is needed is an improved design for an OTFT, and display using the same and an improved method of making that overcomes these problems.